Consumer demand for smaller electronic devices has led to various miniaturization efforts in the field of semiconductor manufacturing. With the miniaturization, plasma process, e.g., plasma etching or deposition processes, are increasingly applied in the manufacturing process of an integrated circuit (IC) chip. Plasma includes ions that flow through the material being processed, for example, to the thin oxide under a gate structure. The thin oxide may breakdown or it may degrade and cause a threshold voltage (Vt) to shift for a transistor. When the threshold voltage shifts, under same conditions a saturating current for affected transistors is smaller than transistors that are not so damaged by the plasma current. As such, plasma-induced damage (PID) can cause parameter degradation of MOSFETs.
Protection such as diodes may be applied to protect the IC from the PID; however, additional active area for the protection diode layout in a chip is unfavorable to the miniaturization. Further, such circuit level protection may not provide protection during manufacturing. Current solutions to the PID issue are not satisfactory in every aspect.